Meredith Emerson (24) was kidnapped and murdered while hiking in the mountains of northern Georgia

The body of a young woman missing since New Year's Day has been found, and the man charged with her disappearance led investigators to her body Monday evening, officials said.

Gary Michael Hilton told authorities where to find the body of 24-year-old Meredith Emerson, the University of Georgia alumna who went missing New Year's Day while hiking in the north Georgia mountains, said John Cagle of the Georgia Bureau of Investigation.

Meanwhile, state and federal authorities said they are trying to determine whether Hilton may have been involved in at least three other killings in two neighboring states.

Investigators found Emerson's body about 7:30 p.m. Monday, Cagle said, in the 25,000-acre Dawson Forest Wildlife Management Area -- about 30 miles south of the Union County, Georgia, state park where she went hiking.

Investigators have charged Hilton, 61, with kidnapping with intent to cause bodily injury. She vanished after venturing into the mountains with her dog, Ella. Ella was found Thursday in nearby Forsyth County.

Several witnesses told authorities they saw Hilton and Emerson together, letting their dogs play along a hiking trail in Vogel State Park.

Director Vernon Keenan of the Georgia Bureau of Investigation and other law enforcement officials declined to say Monday night whether murder charges are pending against Hilton. They also withheld virtually all details about what Hilton said to authorities and the scene where they found Emerson's body.

"There's a lot going on in the case right now -- the investigation is still going on," said Union County District Attorney Stan Gunter. "A lot of decisions have to be made."

Hilton remained in jail Monday night.

Several hours earlier, he appeared in court in shackles and an orange prison jump suit. He did not speak as Judge Johnie Garmon read the charges against him. Garmon said surveillance video had identified Hilton as he tried to use one of Emerson's credit cards at a bank in Canton, Georgia on January 5.

Authorities arrested Hilton after finding bloodstained clothes consistent with what Emerson had been wearing when she went missing, according to a criminal warrant filed Saturday.

Investigators also found Emerson's black leather wallet containing her identification cards in a convenience store trash bin in the Forsyth County city of Cumming, Georgia.

The warrant alleges that Hilton made a phone call Friday from a pay phone at that convenience store.

The bin is next to a grocery store parking lot where Emerson's Labrador mix was found wandering Friday, the warrant said.

The animal was positively identified through an implanted microchip, according to officials.

When Hilton's 2001 minivan was searched, agents "determined that the rear seat belt had been cut out," the warrant said. "Hilton was attempting to vacuum the vehicle and wash portions of it with a bleach and water solution."

Hilton was taken into custody Friday at a convenience store in suburban Atlanta.

Also Monday, federal, Georgia and North Carolina investigators met in nearby Cleveland, Georgia, to "compare notes" on the Emerson case and a similar case from a few months ago in North Carolina, according to FBI special Agent Greg Jones.

In the North Carolina case, an elderly couple -- John and Irene Bryant -- disappeared after going for a hike in Mount Pigsah National Forest. Her body was found near the couple's car. John Bryant's body has not been found, but Keenan referred to the case Monday night as a "double homicide."

Investigators have a bank video of a man wearing a yellow jacket -- believed to have belonged to John Bryant -- while using the Bryant's ATM card.

Witnesses who saw Hilton on the trail with Emerson on the day she disappeared said he was wearing a yellow jacket.

On Monday night, Keenan said Georgia authorities also plan to meet with law enforcement officials from Florida to share details about a similar killing there.